Screw-driver



' nick or slot of the UNITED. STATES PHILLIP NADIG, or ALLESTOWN, PENNSYLVANIA.

SCREW-DRIVER,

SPECIFICATION forming part of Letters Patent No. 267,709, dated November 21, 1882. Application filed July as, 1822 (No model.)

To all zrhom it may concern:

Be it known that I,- PHILLIP NADIG, a citizen of the United States, residing at Allentown, in the county of Lehigh, state ofienns vlvania, have invented a new and useful Improvement in Screw-Drivers, which improvement is fully set forth in the following specification,an d accompanyingdtawings, in which- Figures 1 and 2 are side elevations of the screw-driver embodying my invention.

Similar letters of reference indicate corre sponding pnrts in the two figures.

The object ofniy invention is to prevent the slipping of a screwdriver from the nick or slot of the head ofascreugand increase the strength of the point or plate of the driver.

The invention consists in providingthe point or working end of the driver with a bitingsnrface, which engages with the wall of the screw in such manner as to interlock therewith and cause a firm connection of the parts.

' eferring to the drawings,

A represents a screw driver,

which, excepting as far as my invention relates to it, is of usual form and construction. On one or both sides of the 1 point portion or working end of the shank of the driver are serrations, roughenings, or tile cuts a, forming biting-surfaces, which, when i said pointer end is inserted in the nick or slot of the head of the screw and the driver is rotated, engage with the metal of the walls of said nick or slot and interlock therewith, thus causing the driver to take firm hold of the screw and be prevented from slipping there-. from, the advantages of which will be apparent to and appreciated by those who have used the smooth-sided. screw-driver and had it constantly slip from the head of the screw.

The surfaces a may also be used as files, thus adding to the convenience ofthe tool. Furthermore, as the driver does not slip, the working point or end may be greatly in creased over thatofasmooth puint driver, thus adding strength and rigidity to the driver, the serrations also adding further strength and rigidity thereto.

Having thus described claim as new,- Patent, is-

A screw-driver provided at the point portion or working end of the shank with file-cuts my invention, what I and desire to secure by Letters and for the purpose set forth;

PHILLIP NADIG.

Witnesses:

EDWARD Runs, Trros. P. Wilson.

the taper of a, forming a biting-surface, substantially as 

